Anti-icing composition

ABSTRACT

An anti-icing composition, useful as a gasoline additive, comprising 30-90 weight % of a gasoline soluble organic compound of the formula Z-OH and 10-70 weight % of a gasoline soluble polycarboxy hydrocarbon having 25-75 carbon atoms and at least ten carbon atoms per carboxy group, Z containing about 4-180 carbon atoms and being selected from aliphatic hydrocarbyl, hydroxyaliphatic hydrocarbyl, hydro-poly(oxyalkylene), alkyl poly(oxyalkylene) and alkylphenyl poly(oxyalkylene), for example, an anti-icing composition comprising 30-90 weight % of linoleic acid dimertrimer acid and 10-70 weight % of dipropylene glycol.

United States Patent 1191 Garth 1 ANTI-ICING COMPOSITION {75] Inventor: Bruce Hollis Garth, Newark, Del.

[73] Assignee: E. I. Du Pont de Nemours & C0.,

Wilmington, Del.

22 Filed: Oct. 6, 1972 211 Appl. No; 295,660

[51] Int. Cl. CIUL 1/02 [58] Field of Search 44/1316. 1, 66, 70, 77

[56] References Cited UNITED STATES PATENTS 2,632,695 3/1953 Landis et a1. .4 44/66 2,786,745 3/1957 Stayner et al, 44/DlG, 1

2,807,526 9/1957 Foreman 44/D1G. 1

2,952,121 9/1960 Mitacek H 44/D1G. 1

3,032,971 3/1962 Shotton 44/DlG, l

[ Dec. 9, 1975 3,270,497 9/1966 Malick A. 44/77 3,416,902 12/1968 Anderson et a1. 44 D1G. 1

Primary ExaminerDanie| E1 Wyman Assistant Examiner-Y. Harris Smith 14 Claims, 1 Drawing Figure 15 CURVE D (CUIPOSIlIOlI 0F llVEIllIDlll 5 (MYDRDXYL CUIPOUNDJ I CURVE C COIIPOSITIOII I (EXPECTEDJ \4 CURVE 8 I LBS/1,000 BARRELS U.S. Patent Dec. 9, 1975 3,925,030

I CURVE c I COMPOSITION I (EXPECTED) I5 CURVE n I (COMPOSITION 0F INVENTION I CURVE a (HYDROXYL COMPOUND),

A CYCLES T0 STALL LBS! |,000 BARRELS ANTI-ICING COMPOSITION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to gasoline additives which provide carburetor anti-icing protection.

2. Description of the Prior Art Carburetted internal combustion engines have a tendency to stall during cool wet weather, particularly when they are run at idling speeds before being sufficiently warmed up. The formation of ice in the fuel lines and in the carburetor, particularly on the throttle plate and its adjacent walls, is generally recognized as the cause of such engine stalling. Carburetor icing generally occurs most readily when the atmospheric temperature is about 22-50F., the relative humidity is greater than 65% and the fuel is highly volatile (ASTM Method D-86 distillation of less than about 300F. Although stalling due to carburetor icing is a temporary phenomenon, such stalling usually being eliminated when the engine is thoroughly warm, it is nevertheless undesirable because of the inconvenience, driving annoyance and safety hazard. To prevent or minimize carburetor icing, changes in the carburetor design and- /or rapid means of warming the carburetor may be useful but it is generally recognized that the most effective means of solving the problem is by the use of proper anti-icing additives in the fuel.

Anti-icing additives known in the art include, in addition to the commonly known lower molecular weight alkanols such as methanol, ethanol and isopropanol, other alcohols such as tetrahydrofurfuryl alcohol, polyalkylene glycols, mixtures of glycol ethers, polyalkylene glycol monoethers, alkanolamines, polyamines, amides, amine carboxylate salts, a monoand/or dialkyl phosphate at least partially neutralized with an amine, and combinations such as an alcohol and an ether, benzoic acid and an aminoglycol ether, glycerine and a glycol ether, an N-alkylpyrrolidone and an alkylenediol and a polyhydroxy compound and an aminoamide.

Known anti-icing agents may be deficient for one or more of the following reasons:

1. Most anti-icing additives, and particularly the water soluble additives which function primarily as antifreeze for the fuel, most be used in such high concentrations (up to about 1 weight as to make commercial use uneconomical.

2. Many anti-icing additives promote a high degree of fuel/water interaction, the additive either being readily extracted by water or causing the formation of an emulsion. Since fuels such as gasolines are almost always brought into contact with water, either intentionally or unintentionally, a high level of water interaction is undesirable.

3. With respect to the phosphorus-containing antiicing additives, the presence of phosphorus in the fuel may undesirably affect the operation of a catalytic muffler or thermal reactor which is connected to the engine to control exhaust emissions, for example, hydrocarbons, carbon monoxide and oxides of nitrogen.

Combinations or mixtures of compounds which are disclosed in the art as anti-icing or anti-stalling additives for gasoline include the following. British 997,906 discloses gasolines which have anti-icing characteristics and contain 0.02-0.05% by volume of (a) two or more gasoline soluble diols which are addition products derived from 1 to 3 moles of l,2-propylene oxide and l 2 mole of propanediol-LZ; (b) two or more gasoline soluble alkylene glycol ethers of the formula R- (OCH CH ),,OH wherein R is C alkyl and n is 2 or 3; or (c) a mixture of one or more diols of (a) and one or more ethers of(b). U.S. Pat. No. 3,336,123 discloses gasolines containing as an anti-stalling agent an effective amount of a salt of a linoleic acid dimer or trimer and a dialkylaminopropyl-carboxamide of the formula AcNH-CH CH CH NRR' wherein Ac is a C fatty or naphthenyl acyl group and R and R are the same or different and are C alkyl groups. It also discloses that neither the acid nor the amine components of the salt exhibit anti-icing characteristics. U.S. Pat. No. 3,647,378 discloses gasolines which have improved anti-icing properties and which contain a mixture of benzoic acid and a surfactant type deicer, such as oleyl amine, or a freeze-point depressant type deicer, such as a glycol ether. U.S. Pat. No. 3,653,853 discloses a syn ergistic anti-icing composition for gasoline, which composition contains a polyhydroxy aliphatic alcohol of 2-8 carbon atoms and a C aliphatic amide of a C alkylenediamine, the amount of alcohol being 0.5-5

weight of the amide. U.S. Pat. No. 3,687,644 discloses gasolines containing as anti-icing additives 000001-002 weight of a monoor polycarboxylic acid, or an anhydride, ester, amide or imide derivative thereof, and 0.0l-5 weight of an alcohol, glycol or polyol.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an effective anti-icing gasoline additive composition. It is a further object of the invention to provide an effective, gasoline soluble anti-icing composition which is economical and commercially feasible and which, in addition, provides good anti-rust protection and water interaction properties and is free of any component which may be harmful to exhaust emission control devices. In summary, the present invention residues in a gasoline soluble anti-icing composition which comprises 30-90 weight of a gasoline soluble organic compound of the formula ZOH and 10-70 weight of a gasoline soluble polycarboxy hydrocarbon having 25-75 carbon atoms and at least ten carbon atoms per carboxy group, Z containing about 4-l carbon atoms and being selected from aliphatic hydrocarbyl, hydroxyaliphatic hydrocarbyl, hydro-poly(oxyalkylene), alkyl poly(oxyalkylene) and alkylphenyl poly- (oxyalkylene). Preferred compounds having the formula ZOH include compounds of the formulas ROI-I, HOROH and R (OR ),,OI-I wherein R is C alkyl, R is C alkylene, R is H, C alkyl or C alkyl(phenyl), OR is OCI-I CH OCH CH CH or OCH CHCH n is 2-60 and any two adjacent OR groups are the same or different. The present invention also resides in gasoline containing the aforesaid antiicing composition.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE includes graphs of A cycles to stall (a measure of the effectiveness of the additive in gasoline) vs. concentration of the additive in gasoline for the composition of this invention, for each of the individual components of the composition and for the composition of this invention as anticipated (based upon the effectiveness of each individual component).

DETAILED DESCRIPTION OF THE INVENTION The present invention resides in the discovery of a composition which is useful as a gasoline anti-icing additive. It also resides in gasoline containing such additivc. The composition of the invention is defined above.

The organic hydroxyl compounds of the composition of this invention are gasoline soluble compounds. Since the present composition is required only in very small amounts in gasoline to impart anti-icing characteristics thereto, by gasoline soluble is meant a solubility of at least about 0.002% by weight in gasoline. The useful organic hydroxyl compounds are represented by the formula Z-OH and include the following:

a. monoalcohols of 4-l8 carbon atoms, including both saturated and unsaturated monoalcohols, wherein Z in Z-OH represents an aliphatic hydrocarbyl group of 4-18 carbon atoms. Representative (but non-limiting) examples of Z-OH wherein Z is an aliphatic hydrocarbyl group of 4-18 carbon atoms include butanols, n-octanol, isooctanol, decanols, decenols, dodecanols, dodecenols, tetradecanols, tetradecenols, hexadecanols, hexadecenols, octadecanols and octadecenols. The alcohols of 8-18 carbon atoms are readily available from vegetable oil, beef tallow and whale oil as well as from synthetic sources such as by the oxo-process and the ethylene telomerization process. The preferred monoalcohols are those produced by ethylene telomerization, such alcohols being commercially available generally as mixtures of straight chain saturated alcohols, such as a mixture which typically contains 1% C, H ,Oh, 61% C H OH, 26% C H OH, l 1% C, H OH and 1% C, H OH. For con venience, this mixture will hereinafter be designated as iz-ls b. glycols of 6-10 carbon atoms, wherein Z in Z-OH represents a hydroxyaliphatic hydrocarbyl group of 6-10 carbon atoms. Examples include 2,6-hexanediol, 2,5-hexanediol, 1,6-heptanediol, 2,8-octanediol, 2,7 octanediol, l,8-octanediol, 2,9-decanediol, 2,10- decanediol and l,l0-decanediol.

c. polyoxyalkylene glycols, wherein Z in Z-OH is a hydro-poly(oxyalkylene) group having 6-180 carbon atoms, which can be more simply represented by the formula H(OR ),,OH wherein R is an alkylene group of 2-3 carbon atoms and n is 2-60, preferably 2-20. These glycols can contain oxyalkylene groups of 2 carbon atoms, oxyalkylene groups of 3 carbon atoms, or both. If the latter, they can be present either in a random distribution or in a block distribution. Such glycols are commercially available. The preferred glycols have oxyalkylene groups wherein the alkylene moiety has 3 carbon atoms and is either a l,3-propylene or a 1,2- propylene moiety. The preferred compounds are, therefore, H(OCH CH CH ),,OH and wherein n is 2-60, preferably 2-20. It is to be understood that since polyoxyalkylene glycols generally are prepared by the polymerization of alkylene oxides, the value of n will be an average value. Included in this group of polyoxyalkylene glycols are addition products of maultifunctional hydroxyl compounds and l,2-propylenc oxide. Representative of such addition products are derived from the oxide and trimethylol propane. and

derived from the oxide and pentaerythritol, wherein a and b are such that the total number of carbon atoms is about 15-60.

d. monoalkyl ethers of the polyoxyalkylene glycols of (c). Such alkyl ethers are included in the generic formula previously given, namely, R (()R),,OH. R in the formula for such ethers is C alkyl (preferably C alkyl). Preferred ethers can be represented by the formula wherein R is an alkyl group of 1-18, preferably 12-18, carbon atoms,j and k are integers,j k is 7-12, k is 0-4 and j/k is at least 2. The monoalkyl ethers can be prepared by the addition of an alcohol ROH wherein R is an alkyl group of 1-18 carbon atoms to LIZ-propylene oxide followed, if desired, by addition to ethylene oxide, by procedures well known in the art. Although highly purified individual alcohols of l-lS carbon atoms can be used, it is preferable to use the commercially available mixtures of alcohols discussed above because of their availability and cost. For example, R 0H, l,2-propylene oxide and ethylene oxide react to provide an addition product which can be represented by the formula wherein j and k are as defined above. When both propylene oxide and ethylene oxide are used to prepare the addition product, it is preferred that the ratio of propylene oxide to ethylene oxide in the product be equalito or greater than 2. As an example where the ratio is 2, employing the above formula. is 8 and k is 4. When only l,2-propylene oxide is used, that is. k is 0, preferablyj is 7-l2, more preferably 7.

e. mono(alkylphenyl)ethers of the polyoxyalkylene glycols of (c). They are analogous to the alkyl ethers of (d) and are prepared by the addition of a monoalkylphenol to an alkylene oxide. Such mono(alkylphenyl)ethers are included in the generic formula previously given, namely, R (OR ),,OH, R being as previously described and R being C alkyl(phenyl). Monoalkylphenols are commercially available and are readily prepared by the alkylation of phenol with olefins such as propylene, isobutylene and propylene/isobutylene oligomers. The mono(alkylphenyl)ethers are also commercially available.

The second component of the composition of this invention is a gasoline soluble polycarboxy hydrocarbon having 25-75 carbon atoms and at least carbon atoms per carboxy group. This acid component of the composition can be represented by the formula R"(COOH),,, wherein m is 2-5, preferably 2-3, and the number of carbon atoms and the ratio of carbon atoms to carboxy groups are as stated above. R in the formula can be aliphatic, arylaliphatic (preferably phenylaliphatic), cycloaliphatic or arylcycloaliphatic (preferably phenylcycloaliphatic). A readily available polycarboxy hydrocarbon is a dimer-trimer acid. Dimer-trimer acids are well known in the art, for example, as represented by U.S. Pat. No. 2,632,695 and Goebel, Journal of the American Oil Chemists Society, 24, March, 1947, pages 65-68. Dimer-trimer acids can be produced by the dimerization-trimerization of an unsaturated monocarboxylic acid having, for example, l6l 8 carbon atoms, such as by heating an appropriate dior tri-unsaturated aliphatic carboxylic acid at 330-360C. for 3-8 hours in the presence of a small amount of water. Dimer-trimer acids are actually mixtures of dimer acid, which is believed to contain one or more hydroaromatic ring structures, and trimer acid, which is believed to contain two or more hydroaromatic ring structures. A dimer acid is a dibasic or dicarboxylic acid and a trimer acid is a tribasic or tricarboxylic acid. In carrying out the aforesaid dimerization-trimerization process in a practical fashion, it is difficult to avoid formation of both dimers and trimers. However, by adjusting conditions, such a process can be carried out so as to favor the formation of one or the other acid. For example, under milder conditions, the formation of dimer acid will be favored, in which case the product also usually will contain some unreacted unsaturated acid. Under more rigorous conditions, for example, at higher temperatures and/or heating times, the formation of trimer acid will be favored and essentially 100% conversion of starting unsaturated acid can be achieved. Under such conditions, however, a polymerization type reaction is facilitated and n-mers higher than trimer acid are produced, for example, a tetramer acid. The preferred dimer-trimer acid is derived from linoleic acid. The dimer acid fraction thereof is a dibasic acid containing 36 carbon atoms and the trimer acid fraction thereof is a trimer acid containing 54 carbon atoms. Commercially available linoleic acid dimer acids typically contain about 45-95 wt. of the dimer acid, about 4-25 wt. of higherpolymerized linoleic acids and about 0-4 wt. of monomeric linoleic acid. Commercially available trimer acids typically contain about 75 wt. of the trimer acid and about wt. of the dimer acid and the higher-polymerized acids. Other commercially available materials which are suitable herein include dimerizedtrimerized tall oil residues which typically contain -45 wt. of dimer acid, 10-30 wt. of trimer acid, 0-l5 wt. of monocarboxylic acid and 0-20 weight of rosin acids. Dimertrimer acid" as the term is employed herein is defined as a composition which contains at least 45 wt. of dimer and trimer acids, preferably at least 75 wt. of dimer and trimer acids. Included in the definition are compositions which are comprised substantially of dimer acid and compositions which are comprised substantially of trimer acid.

As already indicated above, the composition of this invention contains about 3090 wt. of a gasoline soluble organic hydroxyl compound and about l0-70 wt. 70 of a polycarboxy hydrocarbon. The choice of a particular ratio of the hydroxyl compound to the acid will depend upon the hydroxyl compound and acid chosen and the degree of antiicing protection desired. Other factors may be taken into consideration in choosing a ratio (as will be obvious from the examples), such as water interaction, anti-rust protection and carburetor keep-clean. The preferred composition of this invention comprises about 30-50 wt. "/e of an organic hydroxyl compound of the formula and about 50-70 wt. of a dimer-trimer acid derived from linoleic acid since it provides the best overall combination of anti-icing protection, water interaction, anti-rust protection and carburetor keep-clean. The most preferred composition contains 3334 wt. of the hydroxyl compound and 66-67 wt. of the dimertrimer acid.

As noted above, gasoline containing the composition of this invention not only provides excellent carburetor anti-icing protection but it provides excellent water interaction, anti-rust and carburetor keep-clean properties. In addition, since the components of the composi tion are compounds which contain only carbon, hydrogen and oxygen, the composition does not contain any element which is known to be detrimental to maximum performance of exhaust emission control devices which may be attached to engines operated with such gasolines.

The amount of the composition of this invention which is added to gasoline will depend upon the particular components used in the composition, the nature of the gasoline and the degree of anti-icing protection desired. For example, winter grade gasolines vary in their volatiles content and those which are higher in volatiles content are more apt to produce carburetor icing. Hence, for such gasolines larger amounts of the antiicing composition are required. With the composition of this invention, anti-icing characteristics have been imparted to gasolines having a 50% distillation point within the range 215C. (according to ASTM Method D-86) by employing 5 pounds of the composition per 1,000 barrels of gasoline (0.002 wt. Preferred amounts of the composition of this invention are in the range 10-20 pounds per 1,000 barrels of gasoline (0.004-0008 wt. The following examples include tests demonstrating the effectiveness of the composition at a use concentration of about 12 pounds per l',000 barrels of gasoline (1 barrel of gasoline contains 42 gallons). One pound per 1,000 barrels of gasoline is approximately 4 parts per million or 0.0004 wt. Higher treating levels, for example, as high as 50-70 pounds per 1,000 barrels of gasoline can be used (0.02-0.028 wt. however, since the composition of this invention is effective at low concentrations, such higher concentrations merely increase the cost of treatment without providing additional anti-icing benefits. The composition can be added to gasoline in any conventional manner, for example, as a physical mixture of the components or as a 50-90 wt. concentrate in a solvent such as benzene, toluene or a xylene. The components of the composition can also be added to the gasoline individually if desired. The gasoline to which the composition is added may consist of straight chain or branched chain paraffms, cycloparaffins, olefms and aromatic compounds, or any mixture of these hydrocarbons. such hydrocarbons being obtainable from straight run naphtha, polymer gasoline, natural gasoline, thermally or catalytieally cracked hydrocarbons and catalytically reformed stock. The gasoline may also contain any of the conventional additives, such as tetraalkyllead antiknock compounds, halogen-containing scavenging agents, corrosion inhibitors, dyes, antioxidants, anti-rust agents, ether anti-icing agents, gum inhibitors. metal deactivators and anti-pre-ignition agents,

EXAMPLE i This example illustrates the anti-icing properties of the composition of this invention. The anti-icing properties were determined by adding the desired amount of the composition to gasoline and using the gasoline in the Engine Carburetor Anti-icing Test described below. The test is carried out by using a Chevrolet 230 cubic inch, 6 cylinder engine. The environment of the carburetor is maintained at 40F. and 95% relative humidity. Thus, essentially water saturated cool air is drawn through the carburetor. The test consists of running the engine on a two part cycle, namely, 20 seconds with open throttle at an engine speed of 1,600 rpm. and 10 seconds with the throttle almost closed at 400 rpmv (idling speed). During the test, ice forms on the throttle plate and on the surrounding carburetor walls and causes the engine to stall by blocking the flow of air when the throttle plate is almost closed during the idling portion of the test. The base gasoline is chosen so that, normally, in the absence of an effective anti-icing additive, engine stalling occurs after about 3-5 cycles. Generally, an additive is considered to be an effective anti-icing agent ifit prevents stalling to about 10 cycles; an excellent anti-icing agent prevents stalling to at least about 25 cycles. The base gasoline used herein had a 50% distillation point of 197F. according to ASTM Method D-86.

The results of this example are summarized in Table I. In the table, the control valve, that is, the number of cycles of stall when gasoline without any additive is used, is recorded as 5, the maximum value obtained in a series of tests. The improvement in anti-icing is the difference between the number of cycles to stall for the gasoline containing the anti-icing agent and the control gasoline (A cycles to stall). The expected increase in the number of cycles to stall (A cycles to stall, expected) is the expected increase in the number of cycles to stall based on the amounts of hydroxyl compound and the dimer-trimer acid added to the gasoline, that is, the expected increase due to the cumulative independent effects of the individual components of the composition. The difference between the actual increase and the expected increase demonstrates the synergistic interaction of the components of the composition.

TABLE I Hydroxyl Wt. 71 ACycles Test Acid Compound Hydroxyl Cycles to Stall, ACycles Nu. lb./l,00() bbl. lb./l,000 bbl. Compound to Stall Expected to Stall 1. Control iii ll, Acid Dimer-Trimer Acid Hydroxyl Compound R ,(OCH

H) OH 2 5 l 3 l2 0 0 7 2 4 l7 0 0 ll 6 5 20 0 0 25+ 20+ 6 0 l0 100 S 3 7 0 l5 l00 l3 8 8 0 17.5 100 25+ 20+ 9 1.6 12.4 87.5 9 6 4 it) 2 l5 38,2 25+ 8 20+ ll 4 8 67 10 4 5 l2 5 10 67 25+ 4 20+ l3 6 6 50 i2 5 7 l4 7 7 50 25+ 4 20+ 8 4 33 i2 3 7 l6 9 5 35 25+ 4 T Acid Dimer-Trimer Acid Hydroxyl Compound H[OCH ..Hl|1OH 8.75 lOO 3 7.5 50 i6 4 ii 8.75 50 4 20+ i IV. Acid Dimer-Trimer Acid Hydroxyl Compound R lOCH Hl,.(OCH,CH ),5OH

V. Acid Dimer-Trimer Acid" Hydroxyl Compound H(OCH, H) OH Vl. Acid DimerTrimer Acid" Hydroxyl Compound Dipropylene Glycol Vll. Acid Dimer-Trimer Acid" Hydroxyl Compound R OH 3 l U 10 l00 lg) tl3 TABLE l-continued Hydroxyl Wt. 72 ACycles Test Acid Compound H ydroxyl Cycles to Stall. ACyclcs No. lb.) 1 .000 bbl. lb./l ,000 bbl. Compound to Stall Expected to Stall 1. Control V111. Acid Dimer-Trimer Acid Hydroxyl Compound 2.5-Hexanediol 34 10 100 9 4 35 1O 67 25+ 5 20+ 36 7.5 7.5 50 9 5 4 37 8.75 8.75 50 25+ 5 20+ 38 ll) 5 33 25+ 6 30+ 1X. Acid Dimcr-Trimer Acid Hydroxyl Compound lso-octylphenol/ethylene oxide Addition Product 39 O 100 9 4 40 8.75 8.75 50 5 I0 41 10 IO 50 25+ 7 25+ X. Acid Dimer-Trimer Acid Hydroxyl Compound Oxo-Decyl Alcohol 42 0 30.0 100 14 9 43 7.5 7.5 50 l l 4 6 44 8.75 8.75 50 25+ 4 l =1 X1. Acid Dimer-Trimer Acid Hydroxyl Compound R -(OCH, H OH 45 2O 0 O 7 2 46 12.5 12.5 50 13 6 8 X11, Acid Dimer-Trimer Acid' Hydroxyl Compound R (OCH,CH) OH 47 2O 0 0 5 0 48 10 1O 50 3 20+ *DimcnTr-imer Acid C dihasic acid (45% l; C monobasic acid (13% )1 C tribusic and higher acids (25% rosin acids 14% residual (3'74 Dimer-Trimer Acid C dihasic acid [75% )1 C trihasic acid (25%]; C monobasic acid (trace) "Dimer-Trimer Acid tribasic acid (90%); C dihasic acid l 10%] EXAMPLE 2 The above data clearly show that the composition of this invention provides better anti-icing protection than would be expected on the basis of the expected contribution of each of the components of the combination. The synergistic anti-icing activity of the combination also is obvious from the FIGURE which is a plot of A cycles to stall vs. concentration of additive. The FIG- URE shows the improvement in anti-icing provided by Dimer-Trimer Acid (Curve A) and by These curves are based on the data of test numbers l-S in Table 1. Curve C represents the anti-icing improvement to be expected upon combination of equal weights of Dimer-Trimer Acid" and hydroxyl compound. Curve D represents the actual anti-icing improvement obtained with a composition containing equal weights of Dimer-Trimer Acid and hydroxyl compound as shown by test numbers 13 and 14 in Table 1. It can be seen from Curve D that the composition containing 7 pounds per 1,000 barrels of the Dimer-Trimer Acid and 7 pounds per 1,000 barrels of hydroxyl compound gave excellent anti-icing improvement of A cycles to stall of 20+ whereas from Curve C it would be expected that the composition should contain 17 pounds per 1,000 barrels each of the Dimer- Trimer Acid" and hydroxyl compound to give the same A cycles to stall of 20+. Similar curves can be drawn from the data summarized in Table l for other ratios of the hydroxyl compound to Dimer-Trimer Acid as well as for other compositions and components to show that similar types of synergistic anti-icing improvements were obtained.

This example illustrates that the composition of the invention, when incorporated into gasoline, in addition to providing excellent anti-icing protection, also provides excellent anti-rust, carburetor keep-clean and water interaction properties. The composition used was a combination of 67% of Dimer-Trimer Acid" and 33% of The composition was added to the gasoline at a treating level of 14 pounds per 1,000 barrels. Rust-preventing characteristics of the treated gasoline were determined according to ASTM Method D665 Procedure A. A mixture of 300 ml. of gasoline and 30 ml. of distilled water, at a temperature of F., was stirred with a cylindrical steel specimen completely immersed therein. The test was run for 24 hours and the area of rust on the specimen was reported as rust. The carburetor keep-clean test (Onan) was carried out in a single cylinder engine to which a controlled amount of exhaust gas from another engine was mixed with air supplied to the test carburetor. The test carburetor throat consisted of a two-piece stainless steel liner fitted around the throttle plate shaft. The liner was easily removed for inspection and rating. The engine was operated under cycling conditions of one minute idling and three minutes part throttle for an overall test period of 2 hours. A visual rating scale of 10 for a clean carburetor and 0 for a very dirty one was used. Generally, a rating of 6 or greater is considered as satisfactory carburetor keep-clean. Water interaction properties of the gasoline containing the composition of the invention were determined by the United States Federal Water Contact Test, Test Method Standard 791B Method 3,9 25,030 l1 12 325 l .7. The fuel to be tested (80 ml.) was shaken with is H, C alkyl or C alkyl(phenyl OR is 20 ml. of a phosphate buffer and after standing for 5 OCH CH- OCH CH CH or OCH CHCH n is 2-60 minutes the change in the volume of the aqueous layer and any two adjacent OR groups are the same or difand the condition of the interface between the two layferent.

ers were noted. The interface condition was rated as 5 3. The composition of claim 2 wherein R is C alfollows: l clear clean interface; lb) a few small clear kyl.

bubbles covering not more than estimated 50% of the 4. The composition of claim 3 wherein R is C interface and no shreds, lace and/or film at the interalkyl and n is 2-20.

face; (2) shred of lace and/or film at interface; (3) S. The composition of claim 1 wherein ZOH is the loose lace and/or slight scum; and (4) tight lace and/or 10 compound having the formula heavy scum. For the water interaction test, the antiicing composition was added to the gasoline at a level of 50 pounds per 1,000 barrels. The results of the tests are summarized below Anti-icing composition at 50 lbs/L000 hhl.

The above data clearly show that the composition of wherein R is C1248 alkyl, j and k are integers, j k is this invention, in addition to providing good anti-icing 7-12, It is 0-4 and j/k is at least 2.

protection at low concentrations (14 lbs] l,000 bbl.), 6. The composition of claim 5 wherein j is 8 and k is also provides good antirust protection, good carbure- 4. tor keepclean and good water interaction properties. 7. The composition of claim 5 wherein j is 7-12 and As shown in Table ll, water interaction tests carried out k is O. with 50 pounds of additive per 1,000 barrels of gasoline 8. The composition of claim 1 wherein Z is C, algave an interface rating of 1; hence, it is apparent that kyl. at lower treating levels, the rating will be equally as 9. The composition of claim 1 wherein ZOH is the good. compound having the formula H(OR OH wherein R The embodiments of the invention in which an excluis C;, alkylene and n is 2-20. sive property or privilege is claimed are defined as fol- 10. The composition of claim 1 wherein the dimer lows: trimer acid is substantially dimer acid.

1. An anti-icing composition for gasoline and com- 11. The composition of claim 1 wherein the dimerprising 30-90 weight of a gasoline soluble organic timer acid is substantially trimer acid. compound of the formula ZOH and 10-70 weight l2. Gasoline containing an amount of the composiof a gasoline soluble dimer-trimer acid of a C unsattion of claim 1 sufficient to impart anti-icing characterurated, aliphatic monocarboxylic acid, ZOH being istics to the gasoline. selected from the group consisting of ROH, HOROH 13. The gasoline of claim 12 wherein the composition and R (OR ),,OH wherein R is (1,. alkyl, R is C alof claim 1 comprises 0.002-002 weight of the gasokylene, R is H, C alkyl or C alkyl(phenyl), R is line.

C alkylene, n is 2-60 and any two adjacent OR 14. The gasoline of claim 13 wherein the composition groups are the same or different. of claim 1 comprises 0004-0008 weight of the gaso- 2. The composition of claim 1 wherein ZOH is the line.

compound having the formula R (OR ),,OH wherein R 

1. AN ANTI-ICING COMPOSITION FOR GASOLINE AND COMPRISING 30-90 WEIGHT % OF A GASOLINE SOLUBLE ORGANIC COMPOUND OF THE FORMULA Z-OH AND 10-70 WEIGHT % OF A GASOLINE SOLUBLE DIMER-TRIMER ACID OF A C16-18 UNSATURATED, ALIPHATIC MONOCARBOXYLIC ACID, Z-OH BEING SELECTED FROM THE GROUP CONSISTNG OF ROH, HOR1OH AND R2(OR3)NOH WHEREIN R IS C4-18 ALKYL, R1 IS C6-10 ALKYLENE, R2 IS H, C1-18 ALKYL OR C1-12 ALKYL(PHENYL), R3 IS-C2-3 ALKYLENE, N IS 2-60 AND ANY TWO ADJACENT OR3 GROUPS ARE THE AME OR DIFFERENT.
 2. The composition of claim 1 wherein Z-OH is the compound having the formula R2(OR3)nOH wherein R2 is H, C1-18 alkyl or C1-12 alkyl(phenyl), OR3 is OCH2CH2, OCH2CH2CH2 or OCH2CHCH3, n is 2-60 and any two adjacent OR3 groups are the same or different.
 3. The composition of claim 2 wherein R2 is C1-18 alkyl.
 4. The composition of claim 3 wherein R2 is C12-18 alkyl and n is 2-20.
 5. The composition of claim 1 wherein Z-OH is the compound having the formula
 6. The composition of claim 5 wherein j is 8 and k is
 4. 7. The composition of claim 5 wherein j is 7-12 and k is
 0. 8. The composition of claim 1 wherein Z is C4-18 alkyl.
 9. The composition of claim 1 wherein Z-OH is the compound having the formula H(OR3)nOH wherein R3 is C3 alkylene and n is 2-20.
 10. The composition of claim 1 wherein the dimer-trimer acid is substantially dimer acid.
 11. The composition of claim 1 wherein the dimer-timer acid is substantially trimer acid.
 12. Gasoline containing an amount of the composition of claim 1 sufficient to impart anti-icing characteristics to the gasoline.
 13. The gasoline of claim 12 wherein the composition of claim 1 comprises 0.002-0.02 weight % of the gasoline.
 14. The gasoline of claim 13 wherein the composition of claim 1 comprises 0.004-0.008 weight % of the gasoline. 